package com.uyayo.framework.common.util.security;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * MD5加密工具类
 * 
 * @author 胡逢君
 * 
 */
public class MD5Util {
	private static Logger log = LoggerFactory.getLogger(MD5Util.class);
	
	public static void main(String[] args) {
		String s = "胡逢君";
		System.out.println(md5(s));
	}

	/**
	 * md5加密
	 * 
	 * @param str
	 * @return
	 */
	public static String md5(String str) {
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(str.getBytes());
			byte[] byteDigest = md.digest();
			int i;
			StringBuffer buf = new StringBuffer("");
			for (int offset = 0; offset < byteDigest.length; offset++) {
				i = byteDigest[offset];
				if (i < 0)
					i += 256;
				if (i < 16)
					buf.append("0");
				buf.append(Integer.toHexString(i));
			}
			// 32位加密
			return buf.toString();
			// 16位的加密
			// return buf.toString().substring(8, 24);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
			return null;
		}
	}

	
	


	  protected static char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', 
	    '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	  protected static MessageDigest messagedigest = null;

	  static {
	    try { messagedigest = MessageDigest.getInstance("MD5");
	    } catch (NoSuchAlgorithmException nsaex) {
	      System.err.println(MD5Util.class.getName() + 
	        "初始化失败，MessageDigest不支持MD5Util。");
	      nsaex.printStackTrace();
	    }
	  }

	  public static synchronized String getMD5String(String s)
	  {
	    return getMD5String(s.getBytes());
	  }

	  public static synchronized boolean checkPassword(String password, String md5PwdStr)
	  {
	    String s = getMD5String(password);
	    return s.equals(md5PwdStr);
	  }

	  public static synchronized String getFileMD5String(File file)
	    throws IOException
	  {
	    InputStream fis = new FileInputStream(file);
	    byte[] buffer = new byte[1024];
	    int numRead = 0;
	    while ((numRead = fis.read(buffer)) > 0) {
	      messagedigest.update(buffer, 0, numRead);
	    }
	    fis.close();
	    return bufferToHex(messagedigest.digest());
	  }

	  public static synchronized String getFileMD5String_old(File file)
	    throws IOException
	  {
	    FileInputStream in = new FileInputStream(file);
	    FileChannel ch = in.getChannel();
	    MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0L, 
	      file.length());
	    messagedigest.update(byteBuffer);
	    return bufferToHex(messagedigest.digest());
	  }

	  public static synchronized String getMD5String(byte[] bytes) {
	    messagedigest.update(bytes);
	    return bufferToHex(messagedigest.digest());
	  }

	  private static synchronized String bufferToHex(byte[] bytes) {
	    return bufferToHex(bytes, 0, bytes.length);
	  }

	  private static synchronized String bufferToHex(byte[] bytes, int m, int n) {
	    StringBuffer stringbuffer = new StringBuffer(2 * n);
	    int k = m + n;
	    for (int l = m; l < k; l++) {
	      appendHexPair(bytes[l], stringbuffer);
	    }
	    return stringbuffer.toString();
	  }

	  private static synchronized void appendHexPair(byte bt, StringBuffer stringbuffer)
	  {
	    char c0 = hexDigits[((bt & 0xF0) >> 4)];

	    char c1 = hexDigits[(bt & 0xF)];
	    stringbuffer.append(c0);
	    stringbuffer.append(c1);
	  }

	  public static String encryptBasedMd5(String strSrc)
	  {
	    String outString = null;
	    try {
	      MessageDigest md5 = MessageDigest.getInstance("MD5");
	      byte[] outByte = md5.digest(strSrc.getBytes("UTF-8"));
	      outString = outByte.toString();
	    } catch (Exception e) {
	      e.printStackTrace();
	    }
	    return outString;
	  }
	  
}
